Germany pulled the plug on three of its last six nuclear power stations on Friday as it moves towards completing a withdrawal from nuclear power that it sped up after the meltdown of a reactor in Fukushima, Japan, in 2011.

"For the German government, natural gas is an important bridging technology on the way to greenhouse gas neutrality against the background of the phase-out of nuclear energy and coal-fired power generation," a government spokesperson said.

"The government's position on nuclear energy remains unchanged. The government remains convinced that nuclear power cannot be classified as sustainable."

While nuclear power produces very low CO2 emissions, the European Commission sought expert advice on whether the fuel should be deemed green given the potential environmental impact of radioactive waste disposal.

A draft of the Commission proposal, seen by Reuters on Saturday, would label nuclear power plant investments as green if the project has a plan, funds and a site to safely dispose of radioactive waste. To be deemed green, new nuclear plants must receive construction permits before 2045.

Investments in natural gas power plants would be deemed green if they produce emissions below 270g of CO2 equivalent per kilowatt hour (kWh), replace a more polluting fossil fuel plant, receive a construction permit by Dec. 31, 2030, and plan to switch to low-carbon gases by the end of 2035.

EU countries and a panel of experts will scrutinise the draft proposal, which could change before it is due to be published later in January. The policy has been mired in lobbying from governments for more than a year and EU countries disagree on which fuels are truly sustainable.

In addition to Germany, other countries including Austria and Luxembourg oppose nuclear power. EU states including the Czech Republic, Finland and France, which gets around 70% of its power from the fuel, see nuclear as crucial to phasing out CO2-emitting coal fuel power.